Recent questions tagged C

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c - linux mkdir function can't authorize full permission

I am testing the mkdir function to create a new directory: folder = mkdir("./linux", 511); or folder = mkdir ... (S_IWGRP | S_IWOTH), any ideas? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - UDP Broadcast in Windows 7 - does it work?

I'm trying to write some code under Windows 7 to broadcast across my local network and can't get the following ... numbytes); Sleep(100); } See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - SIMD code runs slower than scalar code

elma and elmc are both unsigned long arrays. So are res1 and res2. unsigned long simdstore[2]; __m128i *p, ... twice as long as scalar code. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How does MPI_IN_PLACE work with MPI_Scatter?

What exactly does MPI_IN_PLACE do when given as an argument to MPI_Scatter and how should it be used? I can't ... MPI_IN_PLACE let me do this? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - convert array to two dimensional array by pointer

Is it possible to convert a single dimensional array into a two dimensional array? i first tought that will be ... convert it via the pointer? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - What is the Best Practice for malloc?

Which if any of the following are correct and would be considered best practice to create a char string capable of ... malloc(sizeof(char)*100); See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Does #ifdef (or other Preprocessor Directives) Work for Function Declarations (to Test for Function Existence)?

Why doesn't the following code work as expected? void foobar(int); #ifndef foobar printf("foobar exists"); ... an alternative or work-around? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Configuring for a compiler different than the default while running configure

I am compiling the glibc library. Before I could do that, I need to run configure. However, for ... compiler different than the default. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Behaviour of PROT_READ and PROT_WRITE with mprotect

I've been trying to use mprotect against reading first, and then writing. Is here my code #include <sys/ ... Can someone explain this part? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - SSL_library_init cause SIGILL when running under gdb

Trying to debug a program using gdb, it fails reporting SIGILL in OPENSSL_cpuid_setup. With this simple code I have ... a program under gdb ? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How do I specify the include path when I build a program in VSCode?

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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570 views

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c - In a non blocking socket connect, select() always returns 1

I have this code segment that is designed to connect to a server using a socket connection. However if it can not connect ... (0); } return s; } See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - MinGW "The procedure entry point libiconv could not be located ..."

I've got a standard C library that compiles just fine on Mac OS X using gcc. I've examined the C compilers ... setup and not with my project. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Initializing a pointer to a structure

another linked question is Segmentation fault while using strcpy()? I have a structure: struct thread_data{ char ... changed by other threads. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - 64bit/32bit division faster algorithm for ARM / NEON?

I am working on a code in which at two places there are 64bit by 32 bit fixed point division and the result ... could you please help me out? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How does system() exactly work in linux?

I've been reading its man page but haven't yet been successful in figuring out how it works. On calling system ... may be a stupid guess though. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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581 views

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c - Poll() on Named Pipe returns with POLLHUP constantly and immediately

I open a named pipe (fifo created by mkfifo) with non blocking flag (open(...O_NONBLOCK)) then start polling ( ... not have in certain cases). See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - force inline function in other translation unit

This part of the gcc manual is pretty obscure and i can't understand the usage of the forceinline attribute ... from another translation unit ? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Trap Representation, unsigned char and IA64 NaT

Source:Uninitialized garbage on ia64 can be deadly On the ia64, each 64-bit register is actually 65 bits. The extra bit is ... uc + 1 >= 0; } See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Why can't I omit the dimensions altogether when initializing a multi-dimensional array?

In Visual Studio 2010, this initialization works as expected: char table[2][2] = { {'a', 'b'}, ... when initializing a multi-dimensional array? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How to build gnu `libiconv` on & for windows?

I want to build a static library (*.LIB file) GNU libiconv on windows to be used with other libraries in Visual ... do the same for all others. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - scanf dynamic allocation

For whatever reason the following code prints (null): #include <stdio.h> #include <stdlib.h> int main(void) ... compiling with the C11 standard See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Print the environment variables using environ

How to print the environment variables in a C program using "environ". extern char **environ See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Signed Integer Network and Host Conversion

I would like to convert a int32_t from host byte order to network byte order and vice versa. I know about the htonl( ... on Linux and Mac OS X. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - strlen performance implementation

This is a multipurpose question: How does this compare to the glibc strlen implementation? Is there a better way to to ... return (s - z); } See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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679 views

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c - How to link a specific version of a shared library in makefile without using LD_LIBRARY_PATH?

I know that LD_LIBRARY_PATH is evil and it's a good habit to avoid using it. I have a program called server.c on a ... *.ln *.BAK *.bak *.o See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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424 views

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c - What happens if I cast a function pointer, changing the number of parameters

I'm just beginning to wrap my head around function pointers in C. To understand how casting of function pointers ... a cultural shock :-). See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - const causing incompatible pointer type. Why only for double pointers?

This questions has been addressed here. The suggested duplicate and the currently given answers don't address why ... outside of her scope? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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